Misc small fixes to suppress warnings.

Code should now be clean with msvc /W4 and gcc /Wall /Wextra -pedantic with the exception of one deliberate warning in one test.

[SVN r57510]

libs/conversion

@@ -1 +1 @@
-Subproject commit febafb7cb885254b34c2d15875f8756521afaee0
+Subproject commit fce9ad4e1b45aa3dc9490de5d9e8ef6a9a0ac3f3